Hello Brad,
I have quite a few OK 60s and They all seem to run extremely well. If you want to know how to run them in the old style (no transistorisedignition). Look up some past posts by Bob Zambelli. he runs them in the traditional manner with petrol oil mix and has them well sorted. Flloyd Carter is the man for transistorised ignition and both of the above gentleman have given me lots of information and tips via PM's. Contact them for a really in depth help session! I can't praise them enough for the help they gave me.
Looking at some of the other responses, there are one or two points to be aware of. My Super 60s have good compression and start easily by hand. I know of (and have seen) others with much worse compression, that are difficult to handstart. All of the latter will start very easily with an electric starter. I believe that many Super 60s were used in tether car racing, back in the day and some form of starter was invariably used to get them going. The downside of this is that the bearings are fine, but many Super 60s seem to be made with a weak wrist pin (some sort of bronze?). All of my examples are fitted with steel wrist pins. I don't know if OK did this at some stage or if it is an aftermarket conversion. I have never seen anything but steel in this area and I have seven of the OK engines (did I say I liked them?). Any feedback on this would be welcome as I have never been able to work out what was going on here.
The comments on old plugs are a little harsh. In my experience of sparkies, old Champion plugs are a pain, with the center electrode blowing out. Other makes have not had this problem. Modern plugs are well made in this respect, although performance can be down on some of the old plugs, much to my surprise.
About the only available new coils are the Larry Davidson ones, which are a literal Chinese copy of a well known US make of a few years ago (memory not working!). These coils are fine in a traditional setup, but can give huge problems when used with transistorised ignition. Normally they simply don't work, at the risk of Larry suing me. Flloyd told me that the main problem was that the TIP42 transistor had a very low reverse breakdown voltage. He recommended a type with a much higher reverse breakdown. I tried these transistors and although some Larry coils then worked, others did not. Still you can buy them and still use them in non transistor ignition circuits and there they have given me no problems whatsoever, just be careful if you go the transistorised route!
I have not checked the RPM of my engines, but I guess they run at between 6 to 7 thousand RPM. At these revs, they do vibrate much more than modern engines. Don Howie, in Australia, says that with the right prop (I think it was an APC of about 13x6 or 7). The engine gets past this vibration region and smooths out. Unfortunately at higher revs, the integrity of the engine becomes suspect. I have managed to destroy one at these sort of higher revs, so be warned!
About the only real problem with the OK and other similar sized sparkies is the noise! If you run on petrol then a normal expansion type muffler will get the engine very hot. That is about the only reason that I run on castor / methanol brew, they do run cooler on such fuel. A tongue muffler can easily be fabricated for a Super 60, but it doesn't do much muffling and in the UK, noise is bad news. I have copied Bob Zambelli's idea of fitting a very long, large volume expansion exhaust fitted to the fuselage, with the exhaust stack fitting into a slit. A little high temp RTV does a poor sealing function and the noise is then acceptable.
I have been running sparkies in stunt aircraft for a few years now and it is great fun, I am still learning, so any comments or feedback are most welcome.
Regards,
Andrew.